Waste to resource: Engineered ridge gourd peel‐based activated carbon for enhanced cephalexin adsorption

Abstract

This research investigates the efficacy of ridge gourd peel‐derived activated carbon (RGAC), activated with zinc chloride, for the removal of the antibiotic pollutant cephalexin (CFX) from aqueous solutions. Ensuring the elimination of cephalexin residues from aquatic environments is crucial for curbing the emergence of antibiotic‐resistant bacteria and preserving the balance of ecosystems. RGAC exhibits exceptional characteristics, with a surface area of 945.857 m2/g and a pore size of 1.7 nm, as determined through thorough structural analysis. Scanning electron microscopy and Fourier transform infrared analysis confirm the presence of various functional groups on RGAC's surface which aids in adsorption process, while zeta potential analysis indicates a negative surface charge of −18.11 mV. As experimental investigation, batch study was conducted considering distilled water spiked with CFX under standard condition for treatment with RGAC. Impressively, RGAC demonstrates a high CFX adsorption capacity of 37.56 mg/g, also achieving more than 90% CFX removal efficiency. Fitting of the Langmuir isotherm (R2 = 0.9647) and the pseudo‐second‐order kinetics model (R2 = 0.99) reveals strong agreement between theoretical predictions and experimental results. Furthermore, real‐time sampling and regeneration studies underscore RGAC's potential as a commercially viable adsorbent for addressing antibiotic micro‐pollutants in aquatic environments. Throughout six cycles of regeneration studies, a stable pattern emerged, showcasing rejection rates consistently between 81% and 93%. These findings contribute significantly to the advancement of environmentally sustainable water treatment strategies and pollution mitigation efforts.